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08/09/2018, 6:49 am EDT

Global Soil Moisture Outlook

Super drought continues Quebec, Europe and Australia. Wet zones develop northeast Argentina and U.S. Gulf region. Fig. 1: July 2018 global soil moisture % of normal and 3-month trend. Observation discussion: As of August 1st the strongest drought area (globally) based on NOAA percent of normal soil moisture analysis is across Quebec and northern Europe (Fig. 1). Each dry zone has trended drier during the past 3 months. Notable and worsening drought is affecting Australia. East-central Russia has dried quickly and Western Russia has lost their late spring wet soil moisture signature due to a dry summer while dryness has also accelerated near and northeast of the Caspian Sea. Other zones turning much drier are northwest Mexico, Central America, East-central and Southeast Brazil plus Central Chile. The 3-month drier zones outnumber and are somewhat increasingly vast than the wet zones during MAY/JUN/JUL 2018. The primary wet change zones are around the Indian Ocean basin and include Western India, Southeast Asia (the wettest change), Southern Saudi Arabia (due to a tropical cyclone) and central tropical Africa. Wetter zones also affected Southeast Europe, northern Spain and areas south of the Caspian Sea. In North America wetter zones during the past 3 months include the central Great Plains, Mid-Atlantic States and West-central Canada. Fig. 2: July 2018 global soil moisture % of 30-year normal and 3-month forecast. Forecast discussion: The 3-month forecast valid SEP/OCT/NOV 2018 is based on ENSO analog years 1994, 2002 and 2009 coupled with precipitation probability forecasts issued by the International Research Institute for Climate and Society (Fig. 2). In North America two dramatic soil moisture change forecasts over the next 3 months are indicated: Wetter Gulf of Mexico States and drier Northeast U.S. No dramatic change is indicated in the Great Plains. The Northwest U.S. trends drier. In South America there are also 2 dramatic soil moisture change zones: Much wetter in northeast Argentina and southeast Brazil while central portions of Brazil to northwest South America are drier. Central America is also drier. These areas are drier despite a trend toward El Nino due to the cooler SSTA bias causing drier climate in the far eastern equatorial Pacific related to an El Nino Modoki prevalent during the 1994, 2002 and 2009 analog years. In Europe the dry pattern across the U.K., North-central and North Europe continues. The drought in this zone is one of the worst in history and attributed to an upstream upper ridge pattern from a cool upper trough over cool SSTA of the North Atlantic basin just south of Greenland. Southern France to Italy is expected to trend wetter the next 3 months. In Africa a drier pattern is expected in southeast sections while much of the tropical latitudes are wetter. The Australian drought will rank as one of the worst on record given the dry climate forecast through the remainder of 2018. Indonesia also shifts to a sharply drier climate the next 3 months. Previously wet zones of eastern India to Bangladesh trend much drier the next 3 months. A sudden flash drought in West-Central Russia reverses wetter for late 2018. A dry zone east of the Black Sea region reverses wetter.